- the Session has a `pokedex_link_maker` property, whose `object_url`
method is used to make URLs in Markdown
- pokemon.names_table.name is now an ordinary Unicode column
- pokemon.name is a MarkdownString that is aware of the session and the
language the string is in
- pokemon.name_map is a dict-like association_proxy of the above
- move.effect works similarly, with transparent $effect_chance substitution
as before
- as_text() is now a function that takes the session as an argument
- likewise as_html(), which also takes URL makers and the language
- since there should be only one link extension, it is registered by
setting default_link_extension, not appending to markdown_extensions.
This only affects the __html__ attribute.
